I have a 2003 chevy impala and we switched it over from reg 5/30w oil to synthetic 2 weeks ago. Now randomly my Low Oil Pressure light is coming on. Does anyone have an idea of what could be wrong? I am so afraid to drive it. I have had a couple ideas thrown my way, from a sensor goofing up, to the engine not liking the switch over to synthetic oil. Any ideas??

Switching the oil has nothing to do with it. I assume you have checked the oil level????

If the level is good, it very well may be just a faulty oil pressure switch

There has to be better oil for cars than synthetic

other than that i am clueless

hope you get it resolved soon

Yep, the oil level is fine, I've been checking that thinking maybe that was the trouble.

Thanks for the replies! I guess I am off to see a mechanic on Tuesday.

it could be an oil pressure sesor, but it wouldnt be intermitent. it would either function or not. honestly, i would recomend removing the synthetic oil, flushing the engine. and then replaceing it with standard oil. if yo uare trying to get the maximum protection and torque out of your engine, i highly recomend simply using a high-mileage 5w. the 75k an up should be fine. you have to have the right engine to compress and pressure the synthetic oil.

It's a remote possibility but it could be just a faulty oil pump.

Did you use the same 5/30 in the synthetic?

I think he is right the oil presure sending unit is propably going bad,unless You are hearing a loud ticking sound from the engine then don't run it.

pull out pressure sensor and check engine pressure with a gauge

It is probably and oil pressure switch, it can act intermittent. Just like any other electrical component it can have an intermittent open circuit causing failure, which in turn causes the oil light to come on.

Most synthetic oils only have anywhere from 5%-15% actual synthetic blends in them. There is no such thing as a full synthetic oil. It is designed to help lubricate intenral components..Now if you have neglected the intervals and have developed any form of sludge in the motor, the synthetic may have loosened that up causing this possibly. Meaning a seized ring could have come free and is now not sealing the cylinder properly causing a loss in compression. But that would cause a performance issue as well...

GM's are famous for ring to cylinder issues, neglect for a period of time, or even extend two intervals? You can count on some future failure for sure....Be on the safe side and have him do a compression test as well.....

Does a check engine light also appear with that?

Thanks everyone! Yep, we used the same weight for the synthetic oil. The car runs perfectly fine, the low oil pressure light only comes on after I have run it for a long distance (over an hour driving), then turn it off and go again only after the car sitting for 10 minutes or so. The light comes on, stays on for a couple seconds and goes back off again.

When You took off the oil filter, "ya probably got a little medieval on it and disconnected ( or broke off the connector)the wire to the oil pressure sending unit)....the guy who mentioned ticking or knocking sounds is right...if You have no oil pressure, She'll start complaining RIGHT AWAY...IE, You'll know....if it's running with no leaks, creaks, or squeaks, it's probably OK, but get it fixed ASAP-Joe

my lights do not work in my car like the light on top. I know very little about cars. My radio does not work. My speedometer gauge does not work, so my only hunch to this puzzle is that there is a problem with the electric wiring as in my case.

Still confused? I know I am.

Let me give you what little knowledge I have:

DON'T put synthetic oil in an engine that has a lot of miles on it when it has not been running synthetic since it was a baby. (Low mileage, new car)

The changeover can be bad. It will cause more problems with the motor than you realize. Take out the synthetic, and run the same oil you have been the whole life of the car.

If you use say, Valvoline 10W30, then every time you change the oil, or fill it just with a quart, fill it with the same oil, Valvoline 10W30, or whatever you use. ALWAYS USE THE SAME OIL. (Brand, type, etc.)

This is not as true today as it is back when your car was made, but if you are driving an '03, you probably have some good miles on it and should heed my advice.

Hope this helps.

-Roger

Well, that's just a little air bubble in the orifice that feeds the oil pressure sending unit it'll clear up on it's own...don't sweat it...

Agreed....What happens is on a high mileage vehicle, is the internal seals (rubber) are well broken in...Then when you add synthetic on top of it you can count on some near future oil leaks...

As long as you change your oil like you should at said intervals you will be fine....

Synthetic oil will reduce engine heat and friction. in turn giving longer life and better performance, as well to help with gas mileage. But it should be started from the gitgo

Dam double post

Thanks to everyone for all their help. My stupid brother-in-law needs to read the replies. What everyone is telling me is what I tried to tell him. Guess I am not a dumb blonde after all!

You need to check your fuses or fuseable links in the wiring harnesses

Sounds like you have more troubles than me!